Beginner warning: Details follow which you may not wish to read at your current level.

The term Prophecy refers to two different objects in the series. The first and what Muggles most likely expect is the actual utterance, describing things yet to pass. The second is the glass sphere which contains a record, a memory of that prophecy, so that it may be acted upon or its validity checked at a later time.

While Divination, as a means of predicting the future, tries to achieve the same validity as Prophecy, its methods remain laughable to those analyzing them. However, the one person in the series who is capable of Prophecy is the Divination teacher, Professor Trelawney. The mysticism inherent in Divination may make the mind more open to Prophecy, but it is equally possible that a family history of Prophecy impels one towards a career in the codified fakery called Divination.

During the story, we see only two Prophecies in full, both uttered by Professor Trelawney. The first concerns Peter Pettigrew's escape, and his return to "the Dark Lord", and it is couched in terms that Harry is unable to understand until after the named events have occurred. From the reader's perspective at the end of the book, the prophecy's ambiguous term, "his greatest servant", refers to Pettigrew. To the story's characters, however, as to the reader at the time the prophecy is made, Voldemort's greatest servant seemed to be Sirius Black.

The second prophecy was actually made prior to Harry's birth, and concerns Harry and his interaction with Voldemort. We hear this prophecy in Dumbledore's memories, in Harry Potter and the Order of the Phoenix. However, we learn about its existence much earlier, and it is what drives much of the book's action, as Voldemort seems to be blindly reacting to it.

The Battle in the Ministry that forms the climax to Harry Potter and the Order of the Phoenix occurs in the Hall of Prophecies, where copies of all known prophecies are stored in literally hundreds of thousands of small glass spheres, each containing, presumably, a labeled and cataloged prophecy. The battle does result in probably hundreds of these spheres being broken, and fragments of at least two other prophecies can be heard, but amidst the battle, we are unable verify what we are hearing.

A clear distinction must be drawn between Divination, which is taught as an academic subject but which is clearly little better than Muggle fortune-telling, involving the same artifacts and equipment, and Prophecy, which has a basis in reality but is apparently innate and unteachable.

Recordings taken from the memories of witnesses to prophecies, stored in crystal spheres, are kept in the Department of Mysteries, in a store-room associated with the areas used for the study of the mystery of Time. As the areas involved with the study of the Mysteries are interconnected in the same way that the Mysteries are, it is unsurprising that there is also apparently some interconnection between the Prophecy warehouse and the areas devoted to the mysteries of Consciousness and Death.

Prophecy itself seems to be surprisingly common; in the Battle at the Department of Mysteries at the end of Harry Potter and the Order of the Phoenix, it appears that there are many shelves full of recorded prophecies. The prophecy regarding Harry and Voldemort is in row 97 of the prophecy warehouse, and the rows are evidently quite long, and the prophecies small. We can conservatively estimate that there are 200 prophecies on a set of shelves 6 feet (2 metres) high by 3 feet (1 metre) wide. If a row is 60 feet (20 metres) long, each row holds 4,000 prophecies, and with 97 rows there must be approximately 400,000 prophecies in storage. Ollivander's wand shop has been in business since 382 BC, which argues a Wizarding presence in England since at least that time; let us assume that prophecies have been accumulating since then, a total of roughly 2,500 years, or about 160 prophecies a year. If we guess that 1% of the Wizarding population is gifted with the true ability, that would mean somewhere between 30 and 100 prophets are in business at any given time, based on our calculations as to the number of wizards in England – see the article on Hogwarts for the determination of Wizarding population. This would mean that the average prophet or prophetess would be turning out between two and six prophecies every year. (This estimate is actually very low, as it assumes constant Wizarding population, rather than the population growth that England has seen since 400BC. The British population in the Iron Age, about 100 BC, has been estimated at 3 to 4 million, against 58,000,000 in 1997. If the one wizard per 6000 or one wizard in 20,000 rule applied that far back, the UK wizard population would be one tenth the estimates above, leaving us somewhere between 3 and 10 very busy prophets, who probably would have to average between twenty and sixty prophecies a year.) The one prophetess we see, Professor Trelawney, with two valid prophecies in seventeen years, does significantly worse than average.

The author has stated, in an entry on her web site, that she and Sybill had been extremely careful in the wording of the prophecy. The prophecy that drives the entire series is precisely this: The one with the power to vanquish the Dark Lord approaches... born to those who have thrice defied him, born as the seventh month dies... and the Dark Lord will mark him as his equal, but he will have power the Dark Lord knows not... and either must die at the hand of the other for neither can live while the other survives... the one with the power to vanquish the Dark Lord will be born as the seventh month dies...The author notes that it is ambiguous, in that it can refer to either Harry or Neville Longbottom, and in particular that, like the prophecy in Macbeth, if the prophecy had not been made, much of the story would not have happened.

Intermediate warning: Details follow which you may not wish to read at your current level.

We note that both of the prophecies that Trelawney makes are in the same pattern: a preamble, the main prophecy, and a recap of the preamble. We are told that Voldemort is in possession of the first part of the prophecy, but not the second part; it is this pattern, the repetition of the first part, that allows the eavesdropper, later found to be Snape, to hear the first part of the prophecy when he stumbles upon Trelawney mid-utterance. It is Snape who carries the partial prophecy to Voldemort, and we suspect that it was this service that helped move Snape into Voldemort's inner councils.